According to the International Classification of Headache Disorders (ICHD-II), the diagnosis of cluster headache can be made with at least five attacks fulfilling criteria B-D:
B) Severe or very severe unilateral orbital, supraorbital and/or temporal pain lasting 15-180 minutes if untreated.
C) Headache is accompanied by at least 1 of the following:
(i) Ipsilateral conjunctival injection and/or lacrimation.
(ii) Ipsilateral nasal congestion and/or rhinorrhea.
(iii) Ipsilateral eyelid edema.
(iv) Ipsilateral forehead and facial sweating.
(v) Ipsilateral miosis and/or ptosis.
(vi) A sense of restlessness or agitation.
D) Attacks have a frequency from 1 every other day to 8/day.
Additionally, the headaches cannot attributed to another disorder.